talk to me about continuous lighting

here's my situation:

primarily, i'm a painter. my main subject matter is portraiture and the figure and the occassional still life. my studio has two large windows that, thankfully, face north so the light coming in is usually quite nice. however, the light hitting my canvas isn't always ideal and i really want to correct this.

so how does this fit into a photography forum?

i need a versatile and cost effective lighting setup. i want to go with continuous lighting so that i can have more options for lighting a subject for both painting and photographing. also, i'd like to go with a continuous light so that i can focus it through a diffuser, pointed at my canvas so it's lit properly and evenly.

so, can anyone make any reccomendations and, what should i look for? i know heat is a factor but i'm not too concerned about that. however, since i'll be using them for both painting and photography, i'm looking for something that approximates daylight. does this mean i'll also need gels? basically, any advice or tips you can give will be helpful and appreciated.

Have you investigate the $50-100 daylight fluorescent reading lamps? (I use one in my clothes closet so I can see the colors of items when I am dressing in the morning...much better than the non-daylight fluorescent or incandescents!

i haven't, actually. are they really that true to daylight? my only experience with daylight fluorescent light has been with the 48" tubes from home depot which didn't seem close to that temperature at all. i'm not adverse to using them, but that experience left me feeling iffy about them. if its accurate, i'll certainly give it a shot.

also, i want to be able to light a figure. will one of those lamps be enough to do that? the intention there is to use it as more of a directional spot positioned behind a diffuser.

thanks.

Jason77 wrote in post #3211864
i haven't, actually. are they really that true to daylight? my only experience with daylight fluorescent light has been with the 48" tubes from home depot which didn't seem close to that temperature at all. .

Judge for yourself. One photo is using one of the 22w 'daylight' reading lamps, one photo is a GE Sun40 daylight flourescent four 4' tubes with color temp 5000k (in my bathroom), and one is daylight under overcast sky about 6pm. Shot with 20D and AWB, no post processing other than crop and resize for posting.

Jason77 wrote in post #3211864
also, i want to be able to light a figure. will one of those lamps be enough to do that? the intention there is to use it as more of a directional spot positioned behind a diffuser.

When I took these shots, I used ISO100 f/2.8 lens. Daylight was 1/160, artificial light was 1/8-1/15.

Wilt - please re-do the shots of the ColorChecker with the camera set to daylight so that there is no possible variation from shot to shot caused by AWB. That's the only way you can really show whether the light sources are the same or not. I suspect strongly that AWB masked the potential differences.

I'd think a fluorescant light source could give metamerism problems?

SkipD wrote in post #3214070
Wilt - please re-do the shots of the ColorChecker with the camera set to daylight so that there is no possible variation from shot to shot caused by AWB. That's the only way you can really show whether the light sources are the same or not. I suspect strongly that AWB masked the potential differences.

Skip,
Shot-to-shot variations caused by AWB? Could you elaborate? If I have a very controlled subject like the Macbeth filling the frame, why on earth would AWB create differences from one shot to another?...a random number generator in the camera's color programming ?!

I deliberately shot with AWB to see what NET affect could be seen with the camera's neutralizing any difference in color temp. If the camera didn't do it, the photographer would in post processing, after all. So if the net result is indistinguishable difference between the light sources, regardless of whether automation or Otto-mation did it, haven't we shown that the artificial sources are worthy substitutes for daylight?

All light sources differ from each other...even noon vs. near sunset. Or a 3400k photo bulb new vs. a 3400k bulb with 2 hours of burn time! I don't think the point is whether or not the sources are 'different', but to show how similar the net result can be. If you put an 80B filter over the lens and shoot with 3400K bulb, is there some point to be made about the quality of light compared to daylight unfiltered? Or a 3200k household bulb with an 80A filter.

I certainly can shoot the Macbeth again with daylight setting on the camera for the daylight shot, shoot with 5000k setting for the GE F40 bulb shot, and shoot the table lamp with the daylight setting (since I don't recall if the manufacturer has a claim about color temp). Won't have an opportunity to do this until late Friday, though.

René Damkot wrote in post #3214299
I'd think a fluorescant light source could give metamerism problems?

But if the color patches all resemble each other in the three sample shots, this effectively demonstrates the metamerism is not an affect in this case, haven't we? It could have occured, but this test shows that it didn't really. (Admittedly I can see warmth in shot 2 that is not seen in shots 1 or 3.)


BTW, can anyone tell me which is the daylight photo, which is the 5000k source photo, and which is the non-specified 'daylight table lamp' in the above test?

Wilt wrote in post #3214632
BTW, can anyone tell me which is the daylight photo, which is the 5000k source photo, and which is the non-specified 'daylight table lamp' in the above test?

Table lamp
5000k source
Real daylight

mbellot wrote in post #3215715
Table lamp
5000k source
Real daylight

One right out of three. Thanks for trying!

My guess: Daylight, 5000k, Table lamp.

Wilt wrote in post #3214576
Skip,
Shot-to-shot variations caused by AWB? Could you elaborate?

Maybe I misunderstood your purpose with the three shots. What I was expecting to see is how different the three light sources actually are.

Using AWB is (hopefully) like using the eyedropper tool on a white surface when doing RAW conversion and things should even out.

Of course, this assumes all the light sources had relatively even distribution of the wavelengths. Some light sources have peaks and dips in the wavelength distribution and can never be properly corrected for all colors.

Jason,
My wife is actually a landscape painter and uses the daylight fluorescents in her studio. She's quite fussy about her light. I also shoot her artwork (in her studio) for her using the same lights. In fact, I have one of the same fluorescents in my office. The color difference is quite noticeable compared to other home lighting.

Additionally she has an Ott light for her desk, which is supposedly a daylight flourescent and a travelling Ott light to use in hotel rooms when we travel.

René Damkot wrote in post #3216746
My guess: Daylight, 5000k, Table lamp.

We have a winner!

thanks for the replies guys.

wilt, i appreciate the shots but i'd be inclined to agree that the AWB would make for an inaccurate comparison since the camera has the white patch for reference.

titus, its reassuring knowing another painter trusts them for color accuracy. i'm going to look into these more.

i was thinking of trying this:

http://www.adorama.com​/PAFPF.html

the thing is, i need to be able to use it in a few different ways so let me know if this is possible. first, i want to be able to use it as a spot to shoot light onto my canvas without it affecting the light already hitting the subject (i'm assuming this would be possible by making some kind of tube-like attachment for the front). second, i want to be able to use this as a light source (like a spot) on a model for portrait/figure work, for both painting and photography. thats also why i was concerned about the color temperature. if i was using this just for photography, i wouldn't worry about it. but since i want to be able to use it as a light source while painting, i need it to be accurate.

so, what do you guys thing about a light like that one? would two of them do what i'm looking for or should i look at something else?